The present invention relates to a battery power source device which is capable of electric power management by performing data transmission and reception between host equipment, which is driven by a battery power source, such as a portable personal computer, and a battery pack acting as the battery power source.
In general, a portable personal computer called a notebook-type personal computer or a mobile computer (hereafter simply referred to as the xe2x80x9cpersonal computerxe2x80x9d) is driven by a battery power source. Employed as the battery power source is a battery pack including a rechargeable battery and a protective circuit for protecting the rechargeable battery from overcharging, overdischarging, or other troubles. In the protective circuit, at the instant when even only one of a plurality of rechargeable batteries connected in series with each other drops in voltage below a predetermined level, output is interrupted regardless of the total voltage in order to protect the rechargeable battery. In a personal computer, however, abrupt power shutdown causes data corruption, and therefore power shutdown needs to be made in accordance with a predetermined procedure. In light of this, a battery pack for use in a personal computer is equipped with a microcomputer incorporating firmware, thereby constituting an intelligent battery which is connected to a personal computer main body via a communication path.
As one example of intelligent batteries, there has been known a smart battery system. The battery pack includes a microcomputer, in addition to the protective circuit, to detect the remaining capacity, voltage, current, temperature, and other data on the rechargeable battery. Moreover, the microcomputer stores control data, and various data on the individual batteries such as the manufacture""s name, serial number, and charging condition. Thereby, transmission and reception of charging/discharging control data on the rechargeable battery is performed between the battery pack, and a smart charger and a power management controller incorporated in the personal computer main body by way of a two-wire synchronous serial communication interface system. This allows the personal computer main body to perform optimal charging/discharging control for the rechargeable battery on the basis of the data transmitted from the microcomputer incorporated in the battery pack. Hence, power-saving control and prevention of deterioration in rechargeable battery quality are achieved. Further, it is possible to avoid a problem attributed to inadvertent power shutdown or the like occurring during the operation of the personal computer using the battery power source.
However, since the data of the battery pack is stored as firmware in a ROM mounted in the microcomputer, even if the need for troubleshooting or performance improvement comes about, the data of the battery pack cannot be updated. The changing of the firmware necessitates replacement of the microcomputer, which cannot be handled by users. Thus, the users are able to cope with neither troubleshooting nor performance improvement on their own, with the result that the data of the battery pack cannot be maintained optimal and up to date.
An object of the present invention is to provide a battery power source device that enables a personal computer main body to implement power management on the basis of optimal and up-to-date battery pack data at all times by making possible rewriting of firmware mounted in the battery pack.
To achieve the above object, according to a first aspect of the present invention, there is provided a battery power source device, constructed as a smart battery device, for performing data transmission and reception between a battery pack, which has a rechargeable battery and a battery management function for controlling charging and discharging of the rechargeable battery, and host equipment in which the battery pack is mounted, the battery pack and the host equipment being connected to each other by a communication path. The battery pack is provided with a rewritable storage device for storing firmware of the battery pack, and a firmware rewriting device for rewriting the firmware stored in the storage device. The host equipment is provided with a firmware transfer device for transferring up-to-date firmware inputted from a data input device to the battery pack via the communication path. In this construction, when the need for troubleshooting or performance improvement comes about, up-to-date firmware is inputted from the data input device. The up-to-date firmware is transferred through the communication path to the battery pack by the firmware transfer device, so that the firmware rewriting device updates the existing firmware. Hence, the battery pack is kept in an optimally and updatedly controlled state at all times under usage.
According to a second aspect of the invention, there is provided a battery power source device, constructed as a smart battery device, for performing data transmission and reception between a battery pack, which has a rechargeable battery and a battery management function for controlling charging and discharging of the rechargeable battery, and host equipment in which the battery pack is mounted, the battery pack and the host equipment being connected to each other by a communication path. The battery pack is provided with a rewritable storage device for storing firmware of the battery pack, and a firmware rewriting device for rewriting the firmware stored in the storage device. The host equipment is provided with an Internet access device for providing access to the Internet; an up-to-date firmware retrieval device for retrieving up-to-date firmware from an appropriate server after reading URL information stored in the storage device; and a firmware transfer device for transferring the up-to-date firmware to the battery pack via the communication path. In this construction, when the need for troubleshooting or performance improvement comes about, up-to-date firmware is retrieved by making access to a designated server using the Internet access device. The up-to-date firmware is transferred through the communication path to the battery pack by the firmware transfer device, so that the firmware rewriting device updates the existing firmware. Hence, the battery pack is kept in an optimally and updatedly controlled state at all times under usage.
In this construction, it is preferable to additionally provide a temporary storage device for temporarily storing up-to-date firmware retrieved over the Internet by the up-to-date firmware retrieval device. By so doing, even if up-to-date firmware cannot be retrieved properly due to abnormality or disconnection of communication lines occurring during downloading, the firmware of the battery pack is prevented from being rewritten based on inadequate new firmware. Since rewriting of the firmware is executed using the up-to-date firmware stored in the temporary storage device after completion of downloading, the battery pack is prevented from being rendered inoperative because of the execution of rewriting based on inadequate new firmware.